Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for transmitting a buffer status report for a bi-directional transmission in a wireless communication system.
Related Art
3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
Vehicle-to-everything (V2X) communication is the passing of information from a vehicle to any entity that may affect the vehicle, and vice versa. This information exchange can be used for a host of safety, mobility and environmental applications to include driver assistance and vehicle safety, speed adaptation and warning, emergency response, safety, traveler information, navigation, traffic operations and demand management, personal navigation, commercial fleet planning and payment transactions. There is significant societal benefit and commercial value to delivering safety, mobility and convenience applications that rely on V2X.
V2X applications span a host of media. Basic elements of V2X are the vehicle and its connectivity to any other intelligent transportation system (ITS) station. Therefore, V2X includes transceivers located on vehicles, mounted on the roadside infrastructure, in aftermarket devices, or within handheld devices. V2X communication may occur in some of contexts of vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) (or other vulnerable road users) communication, or vehicle to home communication (V2H).
The wide variety of use cases cannot only be met with a short-range radio solution working in a peer to peer manner. Some V2X use cases require infrastructure assistance for communication, and some use cases can make use of smaller scale infrastructure such as small cells or methods such as relaying. For this, the 3GPP has a role to play in defining, examining and acting on the variety of use cases to support the V2X effort. 3GPP infrastructure and 3GPP proximity-based services (ProSe) can act in support and enhancement to dedicated short range communications (DSRC) to fulfil many use cases. There is also the opportunity for 3GPP to investigate modifications and enhancements to ProSe to meet or improve the performance of short range communications in terms of spectral efficiency, effective range, bandwidth and throughput, error resiliency, and improved latency.
Accordingly, various methods for performing V2X communication based on 3GPP technology needs to be defined.